1. Field of the Invention
The present application is related to an apparatus for kneading dough and, in particular, to an apparatus for kneading dough into round pieces.
2. Related Art
Such apparatus for round kneading are known. When round kneading of dough pieces, it is further known to use instead of the inner drum provided with deepenings a kneading tool disposed at the summit region of that drum that has receiving openings for the dough pieces, which tool is driven for kneading movement and mostly consists of a kneading plate provided with recesses.
The kneading movement may--as it is known--be performed in different manners: mostly the kneading tool (the above mentioned inner drum or the kneading plate) executes a circular, elliptic or spiral movement in relation to the openings of the drum receiving the dough pieces, by which movement the dough piece disposed within the opening of the drum gets a spherical or ball-like shape. In case of a spiral movement, this movement at its start has small amplitudes which increase by and by.
Within a known apparatus, the members interconnected to a chain are formed by rounded rods, and an endless band covers this rod chain and improves supporting of the dough pieces disposed within the receiving opening of the drum. It is further known, to replace this band by textile hoses disposed under tension over always three supporting rods. These apparatus, in general, have been shown to be sufficient, but have disadvantages when dealing with very weak and sensitive doughs, that is, doughs for making doughnuts, brioches, hamburgers, and the like. Such doughs, in general, are characterized either by very high dough results or by additions of particular ingredients, as sugar, fat, eggs, and the like. Baker's ware produced therewith is subject to high demands for a smooth, clean strip-free surface, and this surface quality, of course, must be already present on the ready kneaded dough pieces.
It has been shown that the described known apparatus do not fully satisfy when producings such baker's ware. A band put over an endless chain of supporting rods is stretched and compressed during its movement at the points of deflection of the endless band chain, because the band is not disposed within the neutral middle zone of the guiding chain driving it. This leads to continuous band stresses and, therefore, to a high wear of the band, and, at the input and output locations, to a corresponding stressing of the dough pieces by the stretching or compressing. Replacing the endless band by textile hoses tightened over individual rods has also not shown to be sufficient, because there is no more a homogeneous, closed surface for supporting the dough pieces. Further, there results an additional open zone in the region of deflections of the supporting rod chain, so that the dough piece is pinched. This is observed also when a kneading band is disposed in front of this deflection region.
It would be indeed possible, to guide an endless band within the neutral zone, however, the effort for this is considerable.
The invention has at its object to improve the support of the dough pieces at the member chain with little effort so that the aforesaid markings of the member chain on the dough pieces and on the baker's ware produced therefrom are avoided. The invention solves this task by the features that the links and, if desired, filler pieces disposed between them, constitute a closed surface at the side facing the drum, which surface is substantially flat, when the support means is in its stretched condition. This closed planar surface constitutes a supporting surface for the dough pieces to be supported, that is practically gap-less and free of kneading recesses, which supporting surface avoids markings at the dough pieces produced by such gaps or recesses. For this, within the spirit of the invention, there exist a plurality of preferred embodiments. On the one hand, the construction according to the invention can be so chosen that each filler piece is constituted by a rod-shaped member different from the links and being held by two neighboring links by positive locking. This results in a construction having very low costs, because these filler rods, for example, of plastics material, can be produced in a simple manner. Further, this construction shows a very high stability and a high self-cleaning effect that, can be still improved by providing each filler piece with a cross section that is delimited by two opposing circular bow sections and a straight line interconnecting them, wherein the filler piece with its cylindric surfaces constituted by the circular bow sections contacts the periphery of the links having a circular cross section, the planar surface constituted by the straight line facing the drum. Self-cleaning occurs mainly at the points of deflection of the endless link chain by the rotational movements of the links in relation to the filler pieces.
Another preferred embodiment consists in that the cross section of each link has a protrusion directed towards the neighboring link and contacting this link to form a closed surface. With respect to the gap-free supporting of the dough pieces without that strips or the like are marked on the dough pieces, this construction is equivalent to the variant described earlier, however, when seen from the standpoint of manufacture, it requires somewhat more effort, because the single links must show a molded part of synthetic plastics material over a metallic core, in order to obtain a dough-rejecting surface. When seen from the standpoint of self-cleaning the first named variant is also better, even if a particular favorable construction is given in which the cross section of the protrusion is delimited on its side facing the neighboring link concavely by an arc of a circle and engages with this side in a two-dimensional manner the neighboring link having a cross section shaped along an arc of a circle, the concavely delimited cross section verging into a planar area facing the drum.
Lastly, there is also the possibility to design the construction that the links are interconnected to a link chain by axes, which axes are spaced apart from each other, the links having protrusions bridging these spaces, which protrusions constitute the closed surface on their side facing the drum. Also this construction meets the requirements for supporting the dough pieces, however, when seen from the standpoint of the danger of contamination, it is less favorable than the two first named variants.